1. Field of the Invention
This invention generally relates to determining the amount of wear in a roller chain. More specifically, the present invention relates to chain wear indicator, which is used to determine when it is time to replace the chain.
2. Background Information
Roller chains are commonly used for transmitting rotational torque from one rotating chain gear or sprocket to a second rotating chain gear or sprocket. When a chain begins to wear, the overall length of the chain becomes longer. This elongation of the chain often results in the chain skipping or popping off the chain sprockets or gears. This results in stoppage of the apparatus or machine utilizing the chain. Moreover, this skipping or popping off of the chain can damage other components of the apparatus.
The most common and easiest way of testing a chain for wear, i.e., elongation, is done by lifting the chain up when it is on the sprocket or gear. If one of the teeth of the sprocket or gear is fully exposed beneath the chain, then the chain is worn out. Of course, this method is very inaccurate. Therefore, various types of devices have been developed to determine the amount of wear that has occurred in the chain. One example is disclosed in German Utility Patent No. 90-16 000. This device is relatively complicated in that it consists of numerous parts. Moreover, this device is relatively expensive to manufacture.
Another device for determining wear in a roller chain is disclosed in German Utility Model No. 91 10 896. This device is very easy to use and relatively inexpensive to manufacture. However, this device not only measures the wear between the link bushings and connecting pins which causes the chain to increase in length, but it also measures the amount of wear that occurs in the rollers. The frictional wear in the rollers of the chain does not result in elongation of the chain and does not significantly affect the performance of the chain. Rather, the elongation of the chain primarily affects the performance of the chain. Accordingly, using this prior art device may result in chains being discarded before the end of their useful life.
Bicycles primarily utilize roller chains for transmitting torque from the rider's pedaling action to the rear wheel via a pair of sprocket assemblies and a roller chain.
In the bicycle racing industry, it is very important to know if a chain needs to be replaced. If the chain is worn out, i.e., elongated, the chain may skip or pop off of the bicycle sprocket or gears and cause the bicycle racer to loose the race. Therefore, bicycle racers need to know precisely when a chain must be replaced.
In view of the above, there exists a need for a chain wear indicator which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.